How to Pour Concrete Over-Existing Concrete Slab?
Apr 18, · Correctly measure the space where you’d want to fill the new concrete, mark the needed height, and accordingly estimate how much concrete would be required. You can also install braces to avoid spillage when you begin pouring the new concrete over the old surface.5/5(10). laying concrete over concrete? by graham kerr (scotland) Q. My workshop floor, used for welding and machinery servicing, is concreted at 4 to 5 inches deep but the finish is very rough and not comfortable to lye down on or kneel. What I want to do is install 2 inches of concrete over the top and power float to .
Become VIP Member. Do you need to remove the ads? As everything in the world, concrete also has a lifespan and it wears out over time. Imperfections forms when the concrete hardens or sinks into the ground. Pouring fresh concrete over the existing concrete is a common way to level out old slabs and patch damage. This includes removing sand, dead leaves, and gravel. Conrcete of the best tools that can be clean all the debris out of crack is a stiff-bristle broom.
Another way to achieve great cleanliness is by using liquid detergent or degreaser when washing the area, to remove conceete spots. We have cleaners meant for concrete use, one needs concrte scrub spot that proves difficult with it. The last step when cleaning is to make the surface wet.
Measure the perimeter of the area to pour the concrete over the existing slab. Depending upon the requirement of the preferred use of the slab and the loads coming upon the slab. The thickness of the slab is designed. The measurements acquired can then be used to estimate the amount of concrete required. The braces are installed around the area to be filled with concrete usually made of wood. It must be ensured that the braces are evenly spread which is can be done by running a bubble or string.
For the thick concrete slab, a wire-mesh is needed on the braces to provide strength. The mixture of water and cement is made in slurry and spread over the existing slab to form a bonding coat between too old and new concrete to be laid. The standard mixture is of water to cement. Fine sand or crushed stone is preferred for small thickness concrete and coarse aggregate is used for concrete of higher thickness. The mixture of aggregate and cement is mixed and poured it all into the existing concrete.
Hand trowel or a paver is used to spread the concrete evenly by pressing it hard. A bonding adhesive is used in the concrete to ensure that the new concrete stick existing concrete successfully. To protect the new-laid concrete from wearing out soon, a protective layer is applied by using curing compound hoq sprayed it all over the surface which usually takes seven days to cure. Pouring a new layer of concrete over how to lay concrete on concrete existing walkway, patio or porch will raise the level by several inches.
If the slab runs up to a door, the raised surface may not provide the necessary clearance for the door to open. For a walkway, raising the level by several inches can throw off its alignment with the driveway, steps or another structure. Adding a slight what is a green dot moneypak scratch card from the driveway to the raised surface helps eliminate a trip hazard and keep debris from collecting in the corner.
A well-poured concrete slab with a deep, sturdy foundation can last for 30 confrete 40 years. Pouring concrete over old concrete instead of directly over a new gravel foundation limits how to lay concrete on concrete ability to maximize the slab's lifespan. The condition of the existing slab is the primary factor that determines how long the new concrete will last. If the foundation beneath the slab is not sound, the new concrefe could sink or develop deep potholes. If new concrete binds to the existing slab, cracks are inevitable.
Keeping the new concrete from binding to the existing slab helps prevent new damage from forming and any damage in the old slab from spreading to the new one. It also ckncrete both slabs the flexibility to shrink and expand when temperatures fluctuate. One straightforward method to prevent the slabs from how to lay concrete on concrete is to lay plastic, sand or other durable material between the two layers.
While pavers, stones and other types of paving materials offer a more decorative look, concrete is valued for its strength and low maintenance.
A slab poured over an existing slab is more vulnerable to frost heave damage and cracks. Patch damages as soon as they develop to prevent them from spreading, and seal the new layer with a deep penetrating sealer to prevent water damage. If you notice long, deep cracks, have a professional evaluate the damage to determine if there's a structural problem.
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The Process of Pouring New Concrete
Apr 17, Concrete. But, we all know how hard it is to maintain concrete surfaces. And, once it starts showing up imperfections — those patches, grime, and cracks look very unsightly. So, you may ask if pouring new concrete over the old one is a better option. However, proper prep work is needed. Anybody can get rid of the existing surface to develop a new one from start to end. But, only a professional can understand and cater to the needs of restructuring. So, if you pour new concrete over the old surface without preparing the one beneath, it will crumble within no time and will lead to another big headache.
No matter how hard concrete gets or how strong it is, there is nothing that can stick it to the older surface. So what can be done?
If you plan on pouring some or a lot of fresh concrete on the existing slab, you cannot miss out on this step — adding a priming coat. A thin overlay, also frequently called as a primer coating, is put onto the existing surface to prime it up. This consists of special bonding agents that help both the new and the old layer to grip together much firmly and for a longer time giving you a new and sturdy concrete foundation.
The rule of thumb is — If the new layer of concrete is going to be less than 3 inches in thickness, it would need a bonding agent to seal the layers together. And, if the new layer of concrete would be more than 3 inches in width, it would not need a binding agent, but a bond breaker. So, to know all the steps involved in pouring fresh concrete onto the existing base, keep reading further. You can sweep off the dirt or debris on the existing surface, use a pressure washer if there are stubborn stains, or apply chemical-based cleaners to scrub any remaining marks, and leave the surface all wet.
You can also install braces to avoid spillage when you begin pouring the new concrete over the old surface. Plus, you can lay a mesh, so you have a precise framework, and it also strengthens the foundation. Also, if the old surface has a lot of cracks , you can use a thin layer of sand, crushed stones, roofing felt paper, plastic sheeting, or Styrofoam. If necessary, level the exiting slab with additives, and then work on dumping a really thin layer of the scratch coat.
This is a mix of water and concrete in parts having a liquid consistency , and it is with this mix that you must prime the existing slab for smoothening and prepping it up. You can additionally mix a bonding adhesive in the final concrete layer to ensure it sticks well. Finally, new concrete is poured over the primer to fill the area you measured. And, do not forget to level it out nicely, so it looks uniform. You can end the process by spraying a curing compound onto the final layer.
It helps preserve wet concrete and is done right after pouring the new layer. For instance, surfaces with larger cracks, heaving or settling conditions, or where height cannot be raised, replacement is a better solution. However, in most cases, you can pour a new layer of concrete onto the existing one. Whether you require the delivery of superior concrete for building a solid foundation for your home or office space or simply need to restore an existing driveway, we have got you covered.
Contact us online or call us today at Search for: Recent Posts How long does ready mix concrete last? Facebook Twitter Instagram Facebook Twitter Instagram. In most cases, the answer is YES! You can do that, but the existing slab must fulfill certain conditions to support a new concrete layer.
The Process of Pouring New Concrete Step 1: Cleaning Old Concrete Surface You can sweep off the dirt or debris on the existing surface, use a pressure washer if there are stubborn stains, or apply chemical-based cleaners to scrub any remaining marks, and leave the surface all wet. Step 3: Pouring a Primer If necessary, level the exiting slab with additives, and then work on dumping a really thin layer of the scratch coat. Step 4: Adding the Top Layer You can additionally mix a bonding adhesive in the final concrete layer to ensure it sticks well.
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